Catalytic formation of isobutane



amete apt. a was 2,335,34d CATALYTIC FQRMATION (9F ISOBKJTANE Robert E. Burk, Cleveland Heights, Ohio, assignor to The Standard Oil Company, Cleveland, 01110, a corporation of Ohio No Drawing. Application February 10, 1942,

-. Serial No. 430,306

2 Claims.

small proportions relative to the propane up to equal volumes or more.

In some cases ethane, butanes, pentanes and higher hydrocarbons or mixtures may be present. The propane or propane-containing gas may be introduced into the catalyst in gaseous form,

.or liquefied propane may be employed.

As an example: Propane was subjected to 100 volume per cent of hydrofluoric acid and a partial pressure of 150 pounds ofboron fluoride, for

2 hours at a temperature of 825 C. The products showed that 11.7 per cent of the propane had To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting fortlrin detail certain illustrative embodiments of the-invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

. tane.

reacted, and 8'7 per cent of the product was isobu- Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any ofthe following claims, or the equivalent of such, be employed.

Propane as available from any convenient source. or in gases containing available propor-' tions of propane, is, in accordance with the present invention, catalyzed to issobutane. In the reaction isobutane is formed, and also a low hydrocarbon. Apparently, the mechanism is as follows:

3C3Hs- 2iC4Hro+CH'4 2CaHa i-C4Hio+C=Ha In some conditions reaction with ethane is pos- The reaction is brought about by subjecting the propane to liquid hydrofluoric acid in which one-half to fifty mol per cent of boron fluoride is dissolved. The action of the hydrofluoric acid catalyst may be controlled with a partial pressure of the boron fluoride, and particularly by variation of the partial pressure. In general, this partial pressure may be in the range 50-300 pounds per square inch, or more, up to 550 pounds. Temperatures suitable for this catalytic operation are relatively low, from'below room temperature up, or -30 to +200 (2., particularly +25 to It is desirable in some cases to carry on the reaction with the propane in the presence of a heavier hydrocarbon. such as kerosene, or hydrocarbon of boiling point above gasoline. Such heavier hydrocarbon may be in amount from very I therefore particularly point out and distinctly claim as my invention: 7

1. A process of converting propane to isobutane which comprises mixing propane in the presence of a hydrocarbon having a boiling point higher than gasoline, with a liquid catalyst comprising liquid hydrogen fluoride promoted by /z to 50 mol per cent of boron trifluoride dissolved in the liquid hydrogen fluoride as the essential catalytic ingredients; said mixing of said propane, higher boiling hydrocarbon and liquid catalyst being-carried out at a temperature of 30 to 200 C. and at a pressure at least sufllcient to maintain the hydrogen fluoride liquid at the temperature employed to convert a substantial amount of the propane to isobutane.

2. A process of converting propane to isobutane which comprises mixing propane in the presence of kerosene with a liquid catalyst comprising liquid hydrogen fluoride promoted by it to mol per cent of boron trifluoride dissolvedin the liquid hydrogen fluoride as the essential catalytic ingredients so as to provide a partial pressure of boron trifluoride of 50 to 300 pounds per.

square inch, said mixing of the propane, kerosene and liquid catalyst being carried out at a temperature of about 25 to C. and at a pressure at least sumcient to maintain the hydrogen fluoride liquid at the temperature employed while regulating the activity of the catalyst by controlling the partial pressure of the boron trifluoride to convert a substantial amount of the propane to isobutane.

ROBERT E. BURK. 

